US 3113512 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Dec. 10, 1963 D. A. NEWMAN 3,113,512
' PLANOGRAPHIC PRINTING Filed Nov. 6, 1953 5b as 147 Z 2171) b r L17 fi h-' IN l EN TOR. DOuyZas- A. AZ-gwman ATTORNE Y6 United States Patent Of Eice 3,ll3,5l2 Patented Dec. 1G, li-lfiS 3,113,512 PLAVOGRAPHH', IRlNTlNG Douglas A. Newman, Glen (love, Nfifl, assiguor to Columhia Ribbon and (Iarbon Manufacturing (Iompany, Inc, Glen Cove, N.Y., a corporation of New York Filed Nov. 6, 1%3, Ser. No. 399,451 4 Claims. (Cl. 161-1492) This invention relates to the ant of facsimile printing, and particularly to the production by facsimile printing methods of an inscribed plate or master from which a. large number of duplicates may be made by a pianographic printing process, and forms a continuation in part of the invention of my U .8. Patent No. 2,713,322 issued July 26, 1955.
Facsimile apparatus, for the purposes of this description, falls generally into two classes. In either case, electrical impulses, which may be sent over communication circuits, are used to provide at the receiving end an exact duplicate of a master image which has been caused, by suitable photo-electric or other means, to give rise to said impulses at the sending end.
In the first form, the impulses at the receiver are transformed into mechanical movement or pressure for actuating a stylus point which correspondingly inscribes the receiving sheet by moving into and out of contact therewith or increasing and decreasing the pressure with which it contacts the same. By means of this form of device, a manifold set, stencil master or image-forming carbon and planographic plate set may be readily inscribed, so that duplication of the received image offers no serious problems.
The second form of facsimile operation, and the one with which my invention is concerned, uses electrical impulses produced in substantially the same fashion as the first form. The receiver, however, differs in that an electrically conductive stylus point is used. Such a stylus may be in circuit with an electroconduotive platen, separated therefrom by a specially prepared record sheet mounted on the platen for continuous contact with the stylus, said sheet being itself electrically conductive, as illustrated in the patent .to Kline No. 2,251,742. On the other hand the stylus may be connected to a high potential, high frequency source to form a corona discharge element which acts on a specially prepared sheet the paper of which is not necessarily conductive as disclosed in the patents to Cooley No. 1,702,595 and Dalton ct al. No. 2,555,321. These sheets have the property of changing their appearance, usually their color, in locmities where the discharge of current through or against them has occurred. By scanning a sheet of either type in synchronization with the scanning operation at the sending device, the local electrically-induced color changes in the sheet may be grouped so as to reproduce the original image scanned by the sending device. This second method of operation is known in the art as facsimile printing, and will be so referred to hereinafter.
While in many cases the production of planographically printed duplicate copies of the image received on the facsimile printer would be desirable, no method for producing them directly and without the intervention of a photographer or copying inscriber has been heretofore devised. The operation of the facsimile device has hence been limited to the production of single copies, duplicates of which could be had only by resorting to the usual expensive and timeconsuming methods which involve recopying of the received inscription by photography or otherwise, or to hectographic copies as disclosed in the patent to Dalton et al. No. 2,398,779, the latter copies being by their very nature relatively impermanent.
It is accordingly an object of my invention to provide a method and equipment for the production of a planographic master by means of facsimile printing apparatus, from which master a plurality of duplicate copies may be made directly.
My invention is concerned with the development of processes and apparatus whereby a planographic printing plate having a base of paper or similar material which is relatively inexpensive and otherwise suitable for routine duplication processes, may have the oleophilic-hydrophilic balance of its surface locally disrupted to form ink-receptive impressions in response to electrical impulses of the character normally employed in facsimile printing apparatus.
My invention comprehends in particular a planographic plate, preferably having a base of paper or the like, constructed in such .a manner that its planographic surface may be subjected directly to the eiiects of electrical impulses and locally altered in such a manner as to provide an ink-receptive image thereon.
A feature of the present invention is the discovery that a mere supercoating of hydrophilic adhesive nature applied to facsimile sheets of known type can be inscribed by usual facsimile printing devices in the known manner and then used to print copies planographically.
Other features and advantages will hereinafter appear.
In the drawing:
FIGURE 1 is a large scale diagrammatic showing of a portion of a facsimile platen with a sheet according to the present invention shown in section mounted thereon.
FIG. 2 is a section illustrating another embodiment of the sheet of the present invention.
FIG. 3 is a view similar to FIG. 1 but illustrating still another embodiment of the sheet of the present invention together with an alter-native type of facsimile device.
One form of my invention is represented in FIG. 1 wherein is shown a planographic plate 15b which may be inscribed directly by the stylus 32 of an electrical recording device having a conductive drum it} upon which the plate 15b is mounted. A source of electrical energy is indicated diagrammatically at 3'3 and has its terminals connected to the stylus 32 and drum 2b respectively. Plate 15b consists of a sheet of paper or like material 151] preferably having such properties of wet-strength and low wet-extensibility as are necessary to its use as a planographic plate. The sheet 16b has further been treated so that it is primarily oleophilic and hydrophobic in char acter, and likewise electrically conductive. A carbon, silver or aluminum impregnated paper which has been treated to give it suitable wet-strength and Wet-extensibility characteristics may profitably serve as the basis for the plate 1151) about to be described. Many papers in use will be found to be somewhat oleophilic in nature. Most, however, are also somewhat hydrophilic. it is preferred, therefore, to standardize the oleophilic-hydrophobic character of the conductive base by impregnating one surface thereof as shown at 18, with a composition consisting of an appropriate oleophilic filler such as zinc oxide, ground in vany suitable oleophilic binder, for example nitrocellulose lacquer. I have found that this treatment provides a surface on the conductive sheet which, when subjected to an electric current, has a definite oleophilic .tendency of a magnitude within limits which are the most suitable for the purpose intended, and which is likewise suitably substantially hydrophobic.
When the conductive and oleophilic characteristics of the sheet 1612 have been established in accordance with the above description, the same is then covered on its oleophilic surface with a coating 17b of a material which is hydrophilic and at the same time susceptible of being locally disintegrated and disperwd in response to the passage of normal electric recording currents therethrough. Such currents are usually in the neighborhood of to 30 milliarnperes at an impressed voltage of 100 to 300 volts. An example of the coating material suitable for this purpose is one having a base of carboxymethyl cellulose, or a metallic salt of the same which has been applied to the web and insolubilized thereon. Preferably the coating further includes plasticizing agents, fillers, and, prior to its application, suitable volatile drying agents. A filler of zinc sulphide, zinc oxide, titanium dioxide, lead thiosulphate or a mixture thereof is found to be a beneficial constituent of the coating 17b in that the same has the effect of rendering the coating locally removable in a positive and precise manner which makes for improved quality in the image produced. The exact effect of the use of such fillers in the hydrophilic coating is not at present known, but it appears that they have a tendency to reduce sofewhat the high resistance that a coating of this character would normally have, and thus start a reliable current flow across the coating which breaks the same down and disperses it. Likewise the presence of the filler particles appears to partially interrupt the coating continuity in such a Way as to render the coating somewhat more friable, whereby the disruptive forces of the electric discharge are permitted to effect a ready separation and dispersal thereof in well-defined areas.
A solution which has been successfully employed to form the locally removable coating 17b and which represents the form presently preferred is as follows:
Formula I Ingredients Parts by Weight Sodium carboxymethyl cellulose 3 Zinc oxide 9 Titanium dioxide 1 Glycerine 3 Methanol 30 Water 65 The solution represented in Formula I above is spread on the sheet 26b and dried to form the coating 17b. Normally the same will then be treated with heavy metal salt solutions or in any other appropriate manner, depending upon the ingredients used, to render the same insoluble in water while remaining hydrophilic.
This formula is given purely by way of example and not limitation and will serve as a rough approximation of the proportions of the various types of ingredients used when equivalents therefor are substituted.
For example various planographic surfacing materials of hydrophilic adhesive character will be found which can be readily substituted for the sodium carboxymethyl cellulose, the thickening or film-forming ingredient of the above formula. Some of the materials which can be used in this fashion are cellulose glycollic acid, i.e. carboxymethyl cellulose as Well as other alkali salts and the aluminum salt thereof. Furthermore other polysaccharide carboxy ethers such as those of starch, gum arabic, gum tragacanth, mesquite gum and larch gum will also prove to be useful. Alginic acid and salts thereof, as well as alkali salts of dibasic acid styrene copolymers, will be found to be useful in this connection. While not to be preferred over the foregoing, polyvinyl alcohols, urea aldehyde condensation products, gum arabic, gelatin and proteinaceous materials such as casein will also be found to be operative for the purpose when placed in water solutions, spread and then rendered insoluble with a suitable coagulant.
When a plate b constructed in this manner is placed on a platen 2b with its conductive surface in intimate contact therewith and when the energized stylus 32 is engaged with the coating 17b the portion of the coating directly beneath the stylus point is disintegrated and removed in response to the flow of electric current in the making circuit with the result that a portion 34 of the oleophilic web is exposed. When the inscription of the plate 15b has been completed it is removed from the platen 20 and appropriately mounted on a planographic printing press where the background formed by the remainder of the coating 17b is wetted and made ink-repellent and the portions 34 receive the oleous ink, so that copies may be made therefrom in the usual manner.
While the coating 17b is described as hydrophilic, it is to be understood that the same preferably consists of a material capable, in and of itself, of forming a planographic surface in the usual manner, i.e. a surface having a hydnophilic-oleophilic balance suitable for direct-imaging planographic work. By this is meant a surface which when dry is capable of accepting and retaining a 'waxy or other image-forming material 35 having an affinity for oleous printing ink and repelling moisture from the parts covered thereby, the remainder of the surface, or background, being still hydrophilic and capable of being moistened to such an extent that it will fail to pick up ink during printing. It is pointed out that the coating which employs carboxymethyl cellulose and any of the various substitutes described above is of this character and the use of the same, or of other coating materials having equivalent properties, is consequently preferred. The reason for this is that such a coating not only acts in the manner of a locally dispersible hydrophilic coating to form the main image due to localized removal by electrical inscription, but the surface may also carry any auxiliary image which it is desired to add by the usual pressure transfer of ink-receptive material thereto as indicated by reference character 35- in FIG. 1.
The invention as illustrated in FIG. 1 and described above sets out the removability or facsimile feature, and the hydrophilic or planographic feature, as being combined in the coating 17!), but it will be understood that the invention also comprehendsthe incorporation of these features in separate coatings if found convenient or desirable. As shown in FIG. 2, a plate is constructed by providing the conductive paper 16b with the oleophilic standardizing coat or impregnation 18 as previously described. To this surface is then applied a facsimile coating 1171? which is disruptable by the electric current passage and which may consist of a dispersion of a suitable filler in a film former. An example of an appropriate solution for this purpose is given by the immediately following formula:
Formula 11 Ingredients Parts by Weight Zinc sulphide 40 Methocel (Methyl cellulose 15 cps. mfg. by
Dow Chemical Co.) 2.5 Water 100.
In place of zinc sulphide, may be used zinc oxide, titanium dioxide or lead thiosulphate, or mixtures of two or more of these ingredients.
When the coating 1171) has been placed and dried, a thin planographic coating 217 b is placed thereover which may be composed, for example, as set out in the following preferred formula:
heated, it becomes water insoluble and forms the water receptive background for planographic printing.
Another convenient manner in which the planographic coating 21715 may be applied is by coating the surface of the plate with a 5% aqueous solution of sodium carboxyethyl cellulose, drying, and then insolubilizing the same by treating with an aqueous solution of cooper salts, aluminum salts, iron salts and chromium compounds in the ratio of about 6:2: 1: 1 respectively.
As explained for the form of the invention illustrated in FIG. 1 the stated formulas for coating 21712 give excellent results and are presently preferred, however, planographic coatings based on the hydrophilic adhesive film formers previously listed may be substituted with somewhat similar effect.
Inscription of plate 115%; is conducted in the same manner as that for plate 151) in FIG. 1, and local removal of portions of coating 11717 due to the electric current passed by the stylus will, it has been discovered, also cause the simultaneous disruption and removal of the overlying portions of the coating 217b, and only such overlying portions, to produce image areas such as 134.
While the placing and insolubilizing of the coating 17b, or of the coating 217!) have been described as occurring prior to recording, the invention also comprehends the preliminary inscription of the sheet by means of the electric current in the facsimile machine, and the subsequent casting of the planograpnic coating which attaches itself firmly to the background areas of the sheet. The image 34, i.e. those portions of a sheet 16b, 18 which were disrupted by current passage, provides a surface area which, for some reason not entirely understood, is not so readily covered by the aqueous coating solution used for forming the coating 7b as is the smooth undisturbed background surface. The disrupted areas thus reject it, at least in part, or at least provide some oleophilic fibrous protrusions above the coating capable of accepting ink even after wetting in the usual planographic printing process. In the case of the form of the invention shown in FIG. 2, the facsimile coating 117 b may be placed prior to inscription by the recording current and locally removed thereby, and the planographic layer 2171) may be formed afterwards to provide a hydrophilic mask surrounding the image and rendering the sheet capable of printing copies on a planographic printing press.
lVhile the plates b and 1151; illustrated in FIGS. 1 and 2 are adapted for use as conductive elements in a closed circuit type of facsimile apparatus, it will be understood that the same may be used equally as well with space discharge or corona type of apparatus as ilustrated in said Cooley Patent No. 1,702,595.
For many reasons it is often preferred to employ the corona or space discharge type of facsimile equipment, and the following embodiments of the invention are intended primarily for use therewith and are at present preferred. As seen in FIG. 3, such equipment may include a recording drum 2% which may be either conductive or nonconductive, and if the former, is usually provided with an insulating surface layer 120. Spaced from the drum far enough to be slightly removed from contact with any sheet mounted thereon is a stylus 32 which is electrically connected to a high voltage, high frequency source 33. The record and master sheet making up this form of the invention is indicated generally by numeral 150 and includes a foundation sheet 160 of paper which is preferably nonconductive since the cost of papers specially treated or specially made to have conductive properties throughout is relatively high. The sheet may have a wet stren th treatment such as melamine formaldehyde if desired, but for very short printing runs of a few copies only, this feature is not entirely essential. To one surface of the paper fee is applied a coating 18s of conductive material which provides a member or stratum for regulating the potential gradient and rendering it uniform over the entire surface of the sheet. This provides for properly controlled and uniform dispersion forces on the facsimile layer. The layer 18c is preferably a coating of substantial body and thickness as contrasted with the impregnation 13 of FIGS. 1 and 2, and its conductivity is relatively high. The layer 18c also includes a binder which has a sizing and fiber-laying effect on the material of the base 160. A number of appropriate materials are available for this purpose, among them are starch, casein, water soluble gums such as gum arabic and methyl cellulose. After the coating lic has been placed, the sheet will preferably be partially dried and calendered to further lay the fibers. The filler content of the coating 18c will normally serve to furnish the conductive property, and to this end will usually be composed of finely divided carbon, e.g. gas black. The presence of the carbon filler in the coating will tend to render the same somewhat oleophobic as well, for a purpose which will presently appear.
It will be noted that the binders used in forming the coating 18c are all water dispersible, and this is to be preferred since it provides for application of the coating 13c directly on the initial pass through the paper making machine, thus making possible important savings in the cost of the sheet.
To the surface of the coating are applied coatings 117b and 21712 which are substantially identical with the facsimile and planographic coatings previously described for FIG. 2 and may also be considered to be constituted according to Formulas II and Ill respectively, or their equivalents as previously stated.
When a plate is constructed according to the immediately foregoing description, and as shown in FIG. 3, and is subjected to facsimile printing inscription by a stylus 32', it is found that the coatings 11711 and 21712 are locally removed to provide image areas 234. The areas 234 are portions where the coating 1180 is exposed, and it has been discovered that these image areas have especially important properties, for in addition to being primarily oleophilic and ink receptive, the surface of the conductive coating 18c appears to be exposed without substantial disruption of the fibers of the sheet lids. In the case of planographic sheets which have been heretofore electrically inscribed the projecting paper fibers which have erupted due to current action have tended to make the image areas temporarily absorptive so that the copies printed have not always been clear and sharp, especially at the beginning of the printing run and before the image has had a chance to become well inked and thus fully repellent to moisture. According to the embodiment illustrated in FIG. 3, however, the fibers are well laid and firmly retained by the conductive coating which by its presence and conductive properties seems to prevent the stylus discharge from disruptively affecting the surface fibers of the paper sheet 16c. Thus the image areas avoid the initial partially absorptive condition which would allow them to become partially and temporarily wetted, and are fully ink receptive from the beginning of the printing run. This is an important feature inasmuch as the number of copies usually required from plates of this sort is small, and it is important that good copies be produced at the start in order to avoid a high percentage waste of copy sheet paper. Furthermore, the absence of fiber ends at the image surface gives copy which is even much sharper and clearer than the ultimate image after it is well developed and well inked when formed on a plate lacking the fiber-laying and conductive layer 180.
While the form of the invention shown in FlG. 3 has been discussed primarily in connection with the space discharge or corona type of facsimile operation, it will be understood that if desired and if the cost is warranted, the sheet He may also be made conductive like the sheet 162: for use in a conventional circuit type of facsimile inscription as illustrated generally in FIG. 1.
While the invent-ion has been described as useful with normal facsimile equipment with the inference that it is to be operated in a conventional manner to provide planogrhaphic masters or plates imaged with matter sent from a remote sending instrument, it will be understood that other uses of the invention are also contemplated. For example, it has been found convenient in some instances to employ both sending and receiving facsimile equipment at one location as a means for making a plate or master which, While an unchanged duplicate of an original, does not require photographic processes, thus avoiding the inconvenience, complications and usual messiness of timed exposures, developing solutions, fixing treatments, drying and the like. It has been found, for example, that by adjusting the transmitting and recording speeds the character definition can be adjusted so that line drawings and halftones will be reproduced giving masters which provide copies of excellent quality substantially approaching the clarity and definition obtainable by use of a planographic master produced by the ordinary photographic imaging process even under the most favorable circumstances.
Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.
1. An electrically inscribable lithographic printing plate comprising a Wet-strength electroconduct-ive paper base having an impregnation on one surface thereof to render said surface oleophilic, said impregnation containing an oleophilic binder material and an oleophilic filler as the essential ingredients thereof, and, on the surface of said impregnation, an adherent electrically-removable coating of such character as to burn away in elemental areas by the application of marking currents thereto, said coating containing as the essential ingredients thereof a water-dispersible adhesive binder material and a filler selected from the group consisting of zinc sulphide, zinc oxide, titanium dioxide, lead thiosulphate and mixtures thereof; and having adhered to the surface of said electrically-removable coatin a thin water-insoluble hydrophilic lithographic surface coating containing as the essential ingredients thereof a hydrophilic colloid and an insolubilizing agent for said colloid; the said electricallyremovable coating being removable during the inscribing of the lithographic printing plate by an electric current whereby the overlying areas of the lithographic surface coating are also removed, and the oleophilic impregnation being not removable by the electric current.
2. An electrically inscribable lithographic printing plate comprising a wet-strength electroconductive paper base having an impregnation on one surface thereof to render said surface oleophilic, said impregnation contain ing nitrocellulose binder material and Zinc oxide filler as the essential ingredients thereof, and, on the surface of said impregnation, an adherent electrically-removable coating of such character as to burn away in elemental areas by the application of marking currents thereto, said coating containing as the essential ingredients thereof a methyl cellulose adhesive binder material and a filler selected from the group consisting of zinc sulphide, zinc oxide, titanium dioxide, lead thiosulphate and mixtures thereof, and having adhered to the surface of said electrically-removable coating a thin water-insoluble hydrophilic lithographic surface coating containing as the essential ingredients thereof a carboxymethyl cellulose compound and an insolubilizing agent for said compound; the said electrically-removable coating being removable during the inscribing of the lithographic printing plate by an elec tric current whereby the overlying areas of the lithographic surface coating are also removed, and the oleophilic impregnation being not removable by the electric QUITHL 3. An electrically inscribable lithographic printing plate comprising a Wet-strength paper base having an electrically-conductive and oleophilic coating adhered thereto, said oleophilic coating containing as the essential ingradients thereof electrically-conductive carbon and an adhesive sizing which lays and retains the surface fibers of the paper base even when the plate is subjected to marking current discharge, and, on the surface of said oleophilic coating, an adherent electrically-removable coating of such character as to burn away in elemental areas by the application of marking currents thereto, said coating containing as the essential ingredients thereof a water-dispersible adhesive binder material and a filler selected from the group consisting of zinc sulphide, zinc oxide, titanium dioxide, lead thiosulphate and mixtures thereof, and having adhered to the surface of said electrically-removable coating a thin water-insoluble hydrophilic lithographic surface coating containing as the essential ingredients thereof a hydrophilic colloid and an insolubilizing agent for said colloid; the said electrically-removable coating being removable during the inscribing of the lithographic printing plate by an electric current whereby the overlying areas of the lithographic surface coating are also removed, and the oleophilic coating being not removable by the electric current.
4. An electrically inscribable lithographic printing plate comprising a wet-strength paper base having an electrically-conductive and oleophilic coating adhered thereto, said oleophilic coating containing as the essential ingredients thereof electricallyconductive carbon and an adhesive sizing which lays and retains the surface fibers of the paper base even when the plate is subjected to marking current discharge, and, on the surface of said olcophilic coating, an adherent electrically-removable coating of such character as to burn away in elemental areas by the application of marking currents thereto, said coating containing as the essential ingredients thereof a methyl cellulose dispersible adhesive binder material and a filler selected from the group consisting of zinc sulphide, zinc oxide, titanium dioxide, lead thiosulphate and mixtures thereof, and having adhered to the surface of said electrically-removable coating a thin water-insoluble hydrophilic lithographic surface coating containing as the essential ingredients thereof a carboxymethyl cellulose compound and an insolubilizing agent for said comound; the said electrically-removable coating being removable during the inscribing of the lithographic printing plate by an electric current whereby the overlying areas of the lithographic surface coating are also removed, and the clanphilic coating being not removable by the electric current.
References Cited in the file of this patent UNITED STATES PATENTS 1,221,780 Wald Apr. 3, 1917 2,251,742 Kline Aug. 5, 1941 2,291,673 Albers et al. Aug. 4, 1942 2,311,889 Toland et al. Feb. 23, 1943 2,313,497 Adrian Mar. 9, 1943 2,398,779 Dalton ct al. Apr. 23, 1946 2,494,053 Mitson et al Jan 10, 1950 2,554,017 Dalton May 22, 1951 2,555,321 Dalton et al. June 5, 1951 2,649,372 Hills Aug. 18, 1953 FOREIGN PATENTS 550,575 Germany May 12, 1932 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No .3 113 512 December 10 1963 Douglas A. Newman It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
Column 3 line 16, for "sofewhat" read somewhat line 39, for "26b" read 16b same column 3 line 73 for "making" read marking column 5 line 1 for "cooper" read copper line 44, for "ilustrated" read illustrated column 6 lines 11 and 12 for "oleophobic" read oleophilic line 72 for "planogrhaphic" read planographic column 8 line 45 for "comound" read compound Signed and sealed this 12th day of May 1964.
ERNEST W, SWIDER EDWARD J BRENNER Attestmg Officer Commissioner of Patents